[Nouveau] nouveau lockdep deadlock report with 5.18-rc6

[Hans de Goede <hdegoede@redhat.com>]

Hi All,

I just noticed the below lockdep possible deadlock report with a 5.18-rc6
kernel on a Dell Latitude E6430 laptop with the following nvidia GPU:

01:00.0 VGA compatible controller [0300]: NVIDIA Corporation GF108GLM [NVS 5200M] [10de:0dfc] (rev a1)
01:00.1 Audio device [0403]: NVIDIA Corporation GF108 High Definition Audio Controller [10de:0bea] (rev a1)

This is with the laptop in Optimus mode, so with the Intel integrated
gfx from the i5-3320M CPU driving the LCD panel and with nothing connected
to the HDMI connector, which is always routed to the NVIDIA GPU on this
laptop.

The lockdep possible deadlock warning seems to happen when the NVIDIA GPU
is runtime suspended shortly after gdm has loaded:

[   24.859171] ======================================================
[   24.859173] WARNING: possible circular locking dependency detected
[   24.859175] 5.18.0-rc6+ #34 Tainted: G            E    
[   24.859178] ------------------------------------------------------
[   24.859179] kworker/1:1/46 is trying to acquire lock:
[   24.859181] ffff92b0c0ee0518 (&cli->mutex){+.+.}-{3:3}, at: nouveau_vga_lastclose+0x910/0x1030 [nouveau]
[   24.859231] 
               but task is already holding lock:
[   24.859233] ffff92b0c4bf35a0 (reservation_ww_class_mutex){+.+.}-{3:3}, at: ttm_bo_wait+0x7d/0x140 [ttm]
[   24.859243] 
               which lock already depends on the new lock.

[   24.859244] 
               the existing dependency chain (in reverse order) is:
[   24.859246] 
               -> #1 (reservation_ww_class_mutex){+.+.}-{3:3}:
[   24.859249]        __ww_mutex_lock.constprop.0+0xb3/0xfb0
[   24.859256]        ww_mutex_lock+0x38/0xa0
[   24.859259]        nouveau_bo_pin+0x30/0x380 [nouveau]
[   24.859297]        nouveau_channel_del+0x1d7/0x3e0 [nouveau]
[   24.859328]        nouveau_channel_new+0x48/0x730 [nouveau]
[   24.859358]        nouveau_abi16_ioctl_channel_alloc+0x113/0x360 [nouveau]
[   24.859389]        drm_ioctl_kernel+0xa1/0x150
[   24.859392]        drm_ioctl+0x21c/0x410
[   24.859395]        nouveau_drm_ioctl+0x56/0x1820 [nouveau]
[   24.859431]        __x64_sys_ioctl+0x8d/0xc0
[   24.859436]        do_syscall_64+0x5b/0x80
[   24.859440]        entry_SYSCALL_64_after_hwframe+0x44/0xae
[   24.859443] 
               -> #0 (&cli->mutex){+.+.}-{3:3}:
[   24.859446]        __lock_acquire+0x12e2/0x1f90
[   24.859450]        lock_acquire+0xad/0x290
[   24.859453]        __mutex_lock+0x90/0x830
[   24.859456]        nouveau_vga_lastclose+0x910/0x1030 [nouveau]
[   24.859493]        ttm_bo_move_to_lru_tail+0x32c/0x980 [ttm]
[   24.859498]        ttm_mem_evict_first+0x25c/0x4b0 [ttm]
[   24.859503]        ttm_resource_manager_evict_all+0x93/0x1b0 [ttm]
[   24.859509]        nouveau_debugfs_fini+0x161/0x260 [nouveau]
[   24.859545]        nouveau_drm_ioctl+0xa4a/0x1820 [nouveau]
[   24.859582]        pci_pm_runtime_suspend+0x5c/0x180
[   24.859585]        __rpm_callback+0x48/0x1b0
[   24.859589]        rpm_callback+0x5a/0x70
[   24.859591]        rpm_suspend+0x10a/0x6f0
[   24.859594]        pm_runtime_work+0xa0/0xb0
[   24.859596]        process_one_work+0x254/0x560
[   24.859601]        worker_thread+0x4f/0x390
[   24.859604]        kthread+0xe6/0x110
[   24.859607]        ret_from_fork+0x22/0x30
[   24.859611] 
               other info that might help us debug this:

[   24.859612]  Possible unsafe locking scenario:

[   24.859613]        CPU0                    CPU1
[   24.859615]        ----                    ----
[   24.859616]   lock(reservation_ww_class_mutex);
[   24.859618]                                lock(&cli->mutex);
[   24.859620]                                lock(reservation_ww_class_mutex);
[   24.859622]   lock(&cli->mutex);
[   24.859624] 
                *** DEADLOCK ***

[   24.859625] 3 locks held by kworker/1:1/46:
[   24.859627]  #0: ffff92b0c0bb4338 ((wq_completion)pm){+.+.}-{0:0}, at: process_one_work+0x1d0/0x560
[   24.859634]  #1: ffffa8ffc02dfe80 ((work_completion)(&dev->power.work)){+.+.}-{0:0}, at: process_one_work+0x1d0/0x560
[   24.859641]  #2: ffff92b0c4bf35a0 (reservation_ww_class_mutex){+.+.}-{3:3}, at: ttm_bo_wait+0x7d/0x140 [ttm]
[   24.859649] 
               stack backtrace:
[   24.859651] CPU: 1 PID: 46 Comm: kworker/1:1 Tainted: G            E     5.18.0-rc6+ #34
[   24.859654] Hardware name: Dell Inc. Latitude E6430/0H3MT5, BIOS A21 05/08/2017
[   24.859656] Workqueue: pm pm_runtime_work
[   24.859660] Call Trace:
[   24.859662]  <TASK>
[   24.859665]  dump_stack_lvl+0x5b/0x74
[   24.859669]  check_noncircular+0xdf/0x100
[   24.859672]  ? register_lock_class+0x38/0x470
[   24.859678]  __lock_acquire+0x12e2/0x1f90
[   24.859683]  lock_acquire+0xad/0x290
[   24.859686]  ? nouveau_vga_lastclose+0x910/0x1030 [nouveau]
[   24.859724]  ? lock_is_held_type+0xa6/0x120
[   24.859730]  __mutex_lock+0x90/0x830
[   24.859733]  ? nouveau_vga_lastclose+0x910/0x1030 [nouveau]
[   24.859770]  ? nvif_vmm_map+0x114/0x130 [nouveau]
[   24.859791]  ? nouveau_vga_lastclose+0x910/0x1030 [nouveau]
[   24.859829]  ? nouveau_vga_lastclose+0x910/0x1030 [nouveau]
[   24.859866]  nouveau_vga_lastclose+0x910/0x1030 [nouveau]
[   24.859905]  ttm_bo_move_to_lru_tail+0x32c/0x980 [ttm]
[   24.859912]  ttm_mem_evict_first+0x25c/0x4b0 [ttm]
[   24.859919]  ? lock_release+0x20/0x2a0
[   24.859923]  ttm_resource_manager_evict_all+0x93/0x1b0 [ttm]
[   24.859930]  nouveau_debugfs_fini+0x161/0x260 [nouveau]
[   24.859968]  nouveau_drm_ioctl+0xa4a/0x1820 [nouveau]
[   24.860005]  pci_pm_runtime_suspend+0x5c/0x180
[   24.860008]  ? pci_dev_put+0x20/0x20
[   24.860011]  __rpm_callback+0x48/0x1b0
[   24.860014]  ? pci_dev_put+0x20/0x20
[   24.860018]  rpm_callback+0x5a/0x70
[   24.860020]  ? pci_dev_put+0x20/0x20
[   24.860023]  rpm_suspend+0x10a/0x6f0
[   24.860025]  ? process_one_work+0x1d0/0x560
[   24.860031]  pm_runtime_work+0xa0/0xb0
[   24.860034]  process_one_work+0x254/0x560
[   24.860039]  worker_thread+0x4f/0x390
[   24.860043]  ? process_one_work+0x560/0x560
[   24.860046]  kthread+0xe6/0x110
[   24.860049]  ? kthread_complete_and_exit+0x20/0x20
[   24.860053]  ret_from_fork+0x22/0x30
[   24.860059]  </TASK>

Regards,

Hans